<!doctype html>
<title>Absolute positioning</title>

<style>

#stage
{
  position: relative;
  display: block;
  width: 400px;
  height: 300px;
  border: 1px dashed black;
}

#square
{
  position: absolute;
  top: 120px;
  left: 200px;
  display: block;
  width: 100px;
  height: 100px;
  background-color: black;
}

</style>

<div id="stage">
  <div id="square"></div>
</div>